Method for oxidizing a substrate surface using oxygen

Abstract

A method for treating a compound semiconductor substrate, in which method in vacuum conditions a surface of an In-containing III-As, III-Sb or III-P substrate is cleaned from amorphous native oxides and after that the cleaned substrate is heated to a temperature of about 250-550° C. and oxidized by introducing oxygen gas onto the surface of the substrate. The invention relates also to a compound semiconductor substrate, and the use of the substrate in a structure of a transistor such as MOSFET.

The invention claimed is: 
     
       1. A method for producing a crystalline oxide layer on III-As, III-Sb or III-P compound semiconductor substrate, comprising in vacuum conditions
 providing a III-As, III-Sb or III-P compound semiconductor substrate having a substrate surface which is clean from amorphous native oxides; 
 forming an In-containing or Sn-containing III-As, III-Sb or III-P compound semiconductor substrate surface by depositing In or Sn onto the III-As, III-Sb or III-P compound semiconductor substrate surface; 
 heating the formed In-containing or Sn-containing III-As, III-Sb or III-P compound semiconductor surface to a temperature of about 250-550° C., and oxidizing it at said temperature of about 250-550° C. by introducing oxygen gas onto the surface of the substrate. 
 
     
     
       2. The method of  claim 1 , wherein the amount of Sn deposited is 0.5-2.0 monolayers. 
     
     
       3. The method of  claim 1 , wherein the amount of In deposited is 1-2 atomic layers thick. 
     
     
       4. The method of  claim 1 , wherein a surface of said III-As, III-Sb or III-P compound semiconductor substrate is cleaned of amorphous native oxides by argon ion sputtering and post-heating to at least 400° C. in ultrahigh vacuum conditions. 
     
     
       5. The method of  claim 1 , wherein a surface of said III-As, III-Sb or III-P compound semiconductor substrate is cleaned by heating to at least 400° C. in ultrahigh vacuum conditions. 
     
     
       6. The method of  claim 1 , further comprising
 depositing an insulator layer above the crystalline oxide layer. 
 
     
     
       7. The method of  claim 6 , further comprising
 forming a gate insulator stack on the substrate, the gate insulator stack including the crystalline oxide layer and the insulator layer.